1. Field of the Invention
This invention relates to the collection and use of thermal energy such as solar energy for the purpose of cooling and heating a heat transfer medium.
2. Description of Prior Art
My previous patent, U.S. Pat. No. 4,270,522 issued June 2, 1981, discloses a heat transfer system wherein solar energy is absorbed in a solar collector and transferred to a remote location at a lower elevation than that of the collector by means of a fluid heat transfer medium. The fluid is motivated by a steam injector activated by vapor produced in the system by a portion of the solar energy. The system is self-regulating so that it has a capability for operating in an efficient range of collector temperatures despite variations in solar radiation. The sole purpose of this prior system is to transfer heat from the collector to the point-of-need discharge heat exchanger for space heating.
This new invention relates to the cooling and heating of a heat transfer medium involving vaporization of a portion of the fluid. Fluids in the vapor state have been used for the cooling of space. For instance a steam jet system using solar energy for cooling of space was investigated by W. P. Green in 1936 and the results reported in "Utilization of Solar Energy for Air Conditioning and Refrigeration in Florida" (Masters Thesis, College of Engineering, University of Florida). The results of the investigation indicated that the Coefficient of Performance was limited to low values hence solar cooling by means of steam jet was not practical.
The use of a steam jet for chilling water is described in an article by H. R. Havmyer in Chemical Engineering 1948, entitled "Do You Know Enough About Steam Jet Engineering?" More recently in the latest (8th edition) of Marks Standard Handbook for Engineers on page 19-10, there is a description of the current state of the art of cooling space by means of steam jets.
A paper describing the use of steam jets for pumping air at low pressures is published in the "Transactions of the American Society of Mechanical Engineers", 358, entitled, "Characteristics of the Steam Jet Vacuum Pump", by L. S. Harris and A. S. Fischer. The ASME article, written in November of 1948, presents technical data relating to the performance ad efficiencies of steam jet vacuum pumps.
Typical steam jet vapor pumps used in practice are motivated by a jet of steam which flows from a source to a receiver, said receiver being maintained at a lower pressure than the source by means of additional pumps, usually steam jet ejectors. Also, conventional mechanical pumps are needed for supplying cold water for condensing vapor discharged from the jet pump. Such steam jet systems as well as the usual absorption and vapor compression systems that use solar energy for the cooling of space are typical of the current state of the art with regards to their size and complexity, hence they are expensive both in regards to the initial cost and subsequent operation and maintenance.
Solar systems designed solely for heating space and hot water are similarly large and complex. For example, it is inferred from a most recent state of the art article in the ASME publication, "Mechanical Engineering", December 1983, entitled, "System Performance for the Supply of Solar Heat", by G. O. G. Lof and S. Karaki, that manufacturing cost of solar heating systems, exclusive of collectors, is rarely less than 80% of the total price, installed, of the solar water heater or space heating system. It is also noted in the same article that solar systems at research and development centers have performed about twice as well as systems installed in routine residential and commercial establishments. The difference being "----mainly due to the soundness of the design, the quality of the installation, and the extent of maintenance required and performed". This conclusion by the authors of this latest ASME article confirms the need for solar energy systems that satisfy the objectives of this present invention.